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Prosthechea
Prosthechea, abbreviated as Psh. in horticultural trade, is a genus in the orchid family (Orchidaceae). Distribution This a neotropical epiphytic genus, occurring from Florida and Mexico to tropical America. Descriptions The genus Prosthechea has only recently (1997; published in 1998) been reestablished by W. E. Higgins as a distinct genus. Previously, the species had been included in different genera : Anacheilium, Encyclia, Epidendrum, Euchile, Hormidium and Pollardia. The status as genus was confirmed by recent data, based on molecular evidence (nuclear (nrITS) and plastid (matK and trnL-F) DNA sequence data) (C. van den Berg et al. 2000) The roots of all Prosthechea species possess a velamen (a thick sponge-like covering) differentiated into epivelamen and endovelamen. Flavonoid crystals were observed in both the roots and leaves. The erect stems form flattened or thickened pseudobulbs. There are 1 to 3 terminal, sessile leaves. The leathery blade is ovate to lanceolate. The flowers form an apical, paniculate raceme with a spathe at the base of the inflorescence . There is a great variety in the flowers of this genus. They may be attached to the stem by a peduncle or may be sessile. They can flower on the raceme at the same time or successively. They can be resupinate (i.e. turned upside down) or not. The sepals are almost equal in length, while the petals can be much slender. The lip is pressed closely (adnate to proximal) to half of the column and shows a callus (a stiff protuberance). The column is 3- to 5-toothed at its top. The are four, almost equal pollinia with an inverted egg shape. There are four stalks (or caudicles) in two pairs. The beak is entire, curved into a half circle and covered with viscous glycoside crystals. The fruits consists of ellipse-shaped to egg-shaped , 1-locular, 3-winged capsules. Culture Plants grow in cool to warm conditions and can be grown in medium size fir bark with perlite. Plant prefers drying periods between watering and bright light is recommended. Lengthen drying period a bit in the winter. Naming The name is derived from the Greek word prostheke (appendix), referring to the appendage on the back of the column. Synonyms #Hormidium Lindl. ex Heynh.(1840). #Anacheilium Hoffmanns.(1842). #Epicladium Small (1913). #Euchile (Dressler & G.E.Pollard) Withner (1998). #Pseudencyclia Chiron & V.P.Castro (2003). #Panarica Withner & P.A.Harding (2004). #Pollardia Withner & P.A.Harding 217 (2004). Species References # Higgins, W. E. (19971998). "A reconsideration of the genus Prosthechea (Orchidaceae)". Phytologia 82: 370–383. # Van der Berg, C. (2001). "Nomenclatural notes on Laeliinae--III. Notes on Cattleya and Quisqueya, and a new combination in Prosthechea". Lindleyana 16 (3:): 142, 143. # PIRES M.D.F.D.O.; SEMIR J.; PINNA G.F.D.A.M.D.; FELIX L.P. (November 2003). "Taxonomic separation of the genera Prosthechea and Encyclia (Laeliinae: Orchidaceae) using leaf and root anatomical features". Botanical Journal of the Linnean Society (3): . 293-303. # Chiron, G.R. (2003). "An Introduction to the Genus Prosthechea". The orchid Review 111 (1250). # Chiron, G. R. (2005). "Contribution a l'etude de Prosthechea section Parviloba (Orchidaceae)". Richardiana 5 (3): 129-153. (in French) # Pabst, G. F., J. L. Moutinho, and A. V. Pinto (1981). "An attempt to establish the correct statement for genus Anacheilium Hoffmanns. and revision of the genus Hormidium Lindl. ex Heynh.". Bradea 3: 173–186. *